package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IVoucherService;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    //提前定义好脚本
    private static  final DefaultRedisScript<Long> SECKILL_SCRIPT;
    //脚本初始化
    static{
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }



    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();
    @Autowired
    private VoucherOrderMapper voucherOrderMapper;

    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }


    private class VoucherOrderHandler implements Runnable{
        String queueName = "stream.orders";
        @Override
        public void run() {
            while(true){
                try {
                    //1.获取队列中的订单信息
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    //2.判断消息获取是否成功
                    if (list==null || list.isEmpty()) {
                        // 如果获取失败，说明没有消息，继续下一次循环
                        continue;
                    }
                    //3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);

                    //4.如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);

                    //4.ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                    /*VoucherOrder voucherOrder = orderTasks.take();*/
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                    handlePendingList();
                    //*throw new RuntimeException(e);*//*
                }
            }
        }

        private void handlePendingList() {
            while(true){
                try {
                    //1.获取队列中的订单信息
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    //2.判断消息获取是否成功
                    if (list==null || list.isEmpty()) {
                        // 如果获取失败，说明没有异常消息，结束下一次循环
                        break;
                    }
                    //3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);

                    //4.如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);

                    //4.ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                    /*VoucherOrder voucherOrder = orderTasks.take();*/
                } catch (Exception e) {
                    log.error("处理Pending-list订单异常",e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        throw new RuntimeException(ex);
                    }
                    //*throw new RuntimeException(e);*//*
                }
            }
        }


    }

    /*private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024*1024);
    private class VoucherOrderHandler implements Runnable{
        @Override
        public void run() {
            while(true){
                try {
                    //1.获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    //2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (InterruptedException e) {
                    log.error("处理订单异常",e);
                    *//*throw new RuntimeException(e);*//*
                }


            }
        }
    }*/

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        // 1.获取用户
        Long userId = voucherOrder.getUserId();

        //2.创建锁的对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //3.获取锁
        //boolean isLock = lock.tryLock(1200);
        boolean isLock = lock.tryLock();
        //4.判断是否获取锁成功
        if(!isLock){
            //获取锁失败，返回错误信息或重试
            log.error("不允许重复下单");
            return ;
        }

        try {
            //获取事务  确保事务功能
            proxy.createVoucherOrder(voucherOrder);

        } catch (IllegalStateException e) {
            throw new RuntimeException(e);
        } finally {
            //释放锁
            lock.unlock();
        }
    }


    @Resource
    private RedissonClient redissonClient;

    private IVoucherService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        // 获取用户
        Long userId = UserHolder.getUser().getId();
        //2.4订单id
        long orderId = redisIdWorker.nextId("order");
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(),String.valueOf(orderId)
        );

        //判断是否为0
        int r = result.intValue();
        if(r != 0){
            //2.1不为0，代表没有购买资格
            return Result.fail(r==1 ?"库存不足":"不能重复下单");
        }

        //TODO 3.获取代理对象
        //获取代理对象（事务）
        proxy = (IVoucherService) AopContext.currentProxy();


        return Result.ok(orderId);
    }

    /*@Override
    public Result seckillVoucher(Long voucherId) {
        // 获取用户
        Long userId = UserHolder.getUser().getId();
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString()
        );

        //判断是否为0
        int r = result.intValue();
        if(r != 0){
            //2.1不为0，代表没有购买资格
            return Result.fail(r==1 ?"库存不足":"不能重复下单");
        }

        //2.2为0，有购买资格，把下单信息保存到阻塞队列
        //2.3创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        //2.4订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        //2.5用户id
        voucherOrder.setUserId(userId);
        //2.6代金券id
        voucherOrder.setVoucherId(voucherId);
        //2.7放入阻塞队列
        *//*save(voucherOrder);*//*
        orderTasks.add(voucherOrder);
        //TODO 保存阻塞队列

        //TODO 3.获取代理对象
        //获取代理对象（事务）
        proxy = (IVoucherService) AopContext.currentProxy();


        return Result.ok(orderId);
    }*/

   /* @Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);

        //2.判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            //表示尚未开始
            return Result.ok("秒杀尚未开始！");
        }

        //3.判断秒杀是否结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            return Result.ok("秒杀已经结束！");
        }

        //4.判断库存是否充足
        if (voucher.getStock() < 1) {
            //库存不足
            return Result.fail("库存不足！");
        }

        Long userId = UserHolder.getUser().getId();
        //为了确保线程安全
        //创建锁的对象
        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId,stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁
        //boolean isLock = lock.tryLock(1200);
        boolean isLock = lock.tryLock();
        //判断是否获取锁成功
        if(!isLock){
            //获取锁失败，返回错误信息或重试
            return Result.fail("不允许重复下单");
        }

        try {
            //获取事务  确保事务功能
            //获取代理对象（事务）
            IVoucherService proxy = (IVoucherService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } catch (IllegalStateException e) {
            throw new RuntimeException(e);
        } finally {
            //释放锁
            lock.unlock();
        }

        //老的方法
        *//*//为了确保线程安全
        synchronized(userId.toString().intern()) {
            //获取事务  确保事务功能
            //获取代理对象（事务）
            IVoucherService proxy = (IVoucherService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        }//*
    }*/

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //5.一人一单的判断
        Long userId = voucherOrder.getUserId();

        //5.1 查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder).count();
        //5.2 判断是否存在
        if (count > 0) {
            //用户已经购买过了
            log.error("用户已经购买过一次！");
            return;
        }

        //6.扣减库存
        boolean success =  seckillVoucherService.update()
                .setSql("stock = stock - 1")  // 类似于set stock = stock - 1
                .eq("voucher_id", voucherOrder).gt("stock",0) // where id = ? and stock > 0
                .update();

        if(!success){
            //扣件失败
            log.error("库存不足！");
            return;
        }


        // 6.创建订单
/*        VoucherOrder voucherOrder = new VoucherOrder();
        //6.1.订单id

        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        //6.2用户id

        voucherOrder.setUserId(userId);
        //6.3代金券id
        voucherOrder.setVoucherId(voucherId);*/
        //写入数据库
        save(voucherOrder);

        //7.返回订单id
        /*return Result.ok(orderId);*/

    }
}
